A well known overload release clutch of this kind, is disclosed in the British Pat. No. 1,111,340. This prior art clutch consists of a driving clutch member, a driven clutch member, a plurality of torque transmitting balls interposed between the mutually opposing surfaces of both members, a plurality of recesses or openings formed in the mutually opposing surfaces for carrying the torque transmitting balls, and a plurality of ball guiding slots or grooves formed in either one of the mutually opposing surfaces of both clutch members.
In an overload release clutch of this type, a torque is normally transmitted from one clutch member to the other by rotation of both clutch members connected together, with the torque transmitting balls engaging the recesses (openings) under the action of biasing means. When the driven clutch member is subjected to an excessive load beyond a predetermined value, the torque transmission between the two members is suspended, because the torque transmitting balls are moved along the respective ball guiding slots and finally move out of the recesses.
In the event the torque transmitting balls have moved out of the recesses due to application of an unusually large load on the driven clutch member, the balls are obliged to engage the surface of the other clutch member with no ball guiding grooves. This causes a relative movement between the torque transmitting balls and the surface of the other clutch member, since the driving clutch member alone is rotated while the driven clutch member is restrained from movement, which results in wearing out of the surfaces of the other clutch member and of the balls, and produces unpleasant frictional noise.